ES2232441T3 - ELECTRODEPOSITE BATHROOMS CONTAINING ITRIUM. - Google Patents

Abstract

Disclosed are improved electrodeposition bath compositions comprising a resinous phase dispersed in an aqueous medium, the resinous phase being comprised of an active hydrogen containing ionic electrodepositable resin and a curing agent, where the improvement comprises the addition to an electrodeposition bath of at least one source of yttrium in an amount of about 10 to 10,000 parts per million of total yttrium based on electrodeposition bath weight. The electrodeposition bath compositions are preferably cationic and provide for excellent corrosion resistance over a variety of metal substrates including untreated steel. Also disclosed is a method of electrocoating a conductive substrate using the improved electrodeposition bath compositions of the invention. Metallic substrates which are coated using the method of the invention are also disclosed.

Description

Electrodeposition baths containing yttrium.

Field of the Invention

The present invention relates to compositions improved coating and, in particular, to baths of electrodeposition containing a resinous phase dispersed in a medium aqueous, the resinous phase comprising an ionic resin electrodepositable, a curing agent for it and a source of yttrium; and its use in the electrodeposition method.

Background of the invention

The electrodeposit as an application method of coatings means the deposit of a forming composition of film on a conductive substrate under the influence of a electrical potential applied.

The electrodeposit has grown in importance in the coatings industry because, compared to means of non-electrophoretic coating, the electrodeposit offers a better use of paint, better protection against corrosion and low pollution environmental.

Initially, the electrodeposition is carried out placing the piece that is covered as an anode. That's why it has been spoken always anodic electrodeposit. However, in 1972, it commercially introduced the cationic electrodeposition. From that At the moment, the cationic electrodeposition has been gaining in popularity continuously and today is by far the method of electrodeposition that prevails. More than 80 percent of all motor vehicles produced worldwide receive a first cationic electrodeposition coating.

Typically, coatings electrodepositables comprise a film-forming polymer electrodepositable and a curing agent in combination with pigments, among others. Pigments that contain lead such as silica lead chromate, basic lead silicate, lead chromate and lead sulfate are frequently used in coatings electro-depositable because they impart excellent corrosion resistance to the coated article electrolytically However, the acid used in the baths of cationic electrodeposition frequently dissolves a portion of the lead pigment forming lead salts that are soluble in the aqueous phase of the electrodeposition bath. These lead salts they are often in the form of ultrafiltrates in the bathroom, which requires its separation and subsequent removal of metallic lead and / or ionic or organic materials that contain lead.

In recent years, due to the sensitivity for the environment, particularly in Europe and Japan, has been ordered the use of lead-free coatings. Although They can achieve excellent quality surface coatings by cationic electrodeposition of lead-free coatings, the removal of lead pigments that inhibit corrosion can give as a result a reduction in corrosion resistance of these coatings, particularly when applied to substrates untreated or poorly pre-treated steel.

U.S. Patent No. 4,789,441 describes a metallic coating on a substrate applied by electrodeposit of composite material of a metal matrix of nickel, cobalt or iron containing CrAIM2 particles, where M_ {2} is yttrium, silicon or titanium. Metal coating by electrodeposit of composite material imparts resistance to substrate corrosion that is used in aggressive media and is particularly useful for coating turbine blades of gas. This "coating" is completely metallic in its nature and must be melted with the substrate at temperatures above 700 ° C, preferably above 1100 ° C, in order of reaching the diffusion of metals deposited in the substrate. These coatings are unsuitable for general use in Common industrial paint applications.

The patent EP-A-554023 describes a composition Coating suitable for use in protection against corrosion for metals in the electrodeposit, composition comprising a film forming binder and, among other materials, a carboxylic acid yttrium salt insoluble in water.

The use of yttrium to improve corrosion resistance of organic coatings Conventional is not known in the art. Nor is it known either the efficacy of yttrium compounds, which are soluble in medium aqueous, as corrosion inhibitors in coatings conventional cationic electrodepositable. It would be advantageous, for therefore, have a lead-free electrodeposition bath that contain a source of yttrium in order to provide a improved corrosion resistance of metal substrates electrolytically coated, especially steel without try.

Compendium of the invention

According to the present invention, a coating composition comprising (a) a resin that contains active hydrogen group and (b) a curing agent that it has reactive functional groups with hydrogen groups asset of (a). The composition contains about 0.005 to 5 percent, preferably not more than 2.5 percent, and more preferably not more than 1.0 percent by weight yttrium (measured as elemental yttrium) based on the weight of the total solids of resin.

In a particular embodiment, the invention is based on an electrodeposition bath, which has a improved corrosion resistance, comprising a resinous phase dispersed in aqueous medium. The resinous phase comprises the following components:

(to)

  an electro-depositable ionic resin containing active hydrogen group, and

(b)

  a curing agent that has reactive functional groups with the         active hydrogen groups of (a). Yttrium compound, which is soluble in aqueous medium, is present in the bath of electrodeposit in an amount of approximately 0.005 percent by weight to about 5 percent by weight or, alternatively, in an amount of about 10 to about 10,000 parts per million total yttrium (measured as elemental yttrium) based on the weight of the electodeposit bath.

A method of electrolytic coating of a conductive substrate that serves as electrode charged in an electrical circuit comprising the electrode and a counter-electrode charged with charge opposite, both submerged in the aqueous electrodeposition tank before described, and metal substrates coated by the method.

Detailed description of the invention

Generally, the electrodeposit bath of the The present invention comprises a resinous phase dispersed in a medium aqueous where the resinous phase comprises the following components:

(to)

  an electro-depositable ionic resin containing active hydrogen group, and

(b)

  a curing agent that has reactive functional groups with the         active hydrogen groups of (a)

where the electrodeposit bath it contains a compound of yttrium, soluble in aqueous medium, in a amount from about 10 to about 10,000 parts per million, preferably no more than about 5,000 parts per million, and more preferably no more than about 1,000 parts per million, of the total yttrium (measured as yttrium elementary).

At levels lower than 10 parts per million of Total yttrium, based on the weight of the electrodeposition bath is not observes an appreciable improvement in the corrosion resistance of electrolytically coated substrate. At higher levels of yttrium 10,000 ppm may adversely affect the stability characteristics and application of the compositions of the electrolytic coating bath.

Soluble yttrium compounds may serve as a source of yttrium in the electrodeposition baths of the invention. Among the examples of yttrium sources, suitable for your use in lead-free electrodeposition baths herein invention are soluble inorganic and organic salts of yttrium such as yttrium acetate, yttrium chloride, yttrium formate, yttrium carbonate, yttrium sulfamate, yttrium lactate and nitrate of yttrium When yttrium is added to a coating bath electrolytic as an aqueous solution, nitrate of Yttrium, an easily available yttrium compound, as a source of yttrium. Other yttrium compounds suitable for use in The electrodeposition baths of the present invention are the organic and inorganic yttrium compounds such as bromide yttrium, yttrium hydroxide, yttrium molybdate, yttrium sulfate, yttrium silicate and yttrium oxalate. They can also be used organo-yttrium and metal yttrium complexes.

In addition to yttrium compounds before mentioned, the electrodeposition baths of the present invention they also contain, as the main film forming polymer, a ionic electrodepositable resin, preferably cationic, which It contains active hydrogen. A wide variety of electrodepositable film-forming polymers and can be use in the electrodeposition baths of the present invention provided they are "water dispersible" polymers adapted to be dissolved, dispersed or emulsified in water. He water dispersible polymer is ionic in nature, that is, the polymer will contain anionic functional groups to impart a negative charge or, as preferred, cationic functional groups to deliver a positive shit.

Among the examples of resins forming film for use in electrodeposition bath compositions anionic are polymers that contain carboxylic acid, solubilized by base such as the reaction product or adduct of a drying oil or fatty acid ester semi-drying with a dicarboxylic acid or anhydride; and the reaction product of an ester of fatty acid, acid or unsaturated anhydride and any unsaturated modifying material additional that also reacts with polyalcohol. They are also suitable interpolymers, at least partially neutralized, of hydroxy-alkyl esters of carboxylic acids unsaturated, unsaturated carboxylic acid and at least one other monomer ethylenically unsaturated. Still another electrodepositable resin suitable comprises an alkyd aminoplast vehicle, i.e. a vehicle that contains alkyd resin and a resin amine-aldehyde. Still another electrodepositable resin Anionic comprises mixed esters of a resinous polyol. These Compositions are described in detail in the Patent U.S. No. 3,749. 657 in column 9, lines 1 to 75 and column 10, lines 1 to 13, which is incorporated herein by reference. Be they can use other acidic function polymers such as phosphate polyepoxide or phosphate acrylic polymers that are well known to those skilled in the art.

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As mentioned before, it is preferred that the ionic electrodepositable resin containing active hydrogen be cationic and able to deposit in the cathode. Between the Examples of such cationic film-forming resins are they include resins containing amine salt group such as reaction products solubilized with polyepoxide acids and primary and secondary amines such as those described in US Patents Nos. 3,663,389; 3,984,299; 3,947,338; Y 3,947,339. Normally, these resins containing salt group of amine are used in combination with a curing agent of isocyanate blocked. The isocyanate can be completely blocked as described in U.S. Patent No. 3,984,299 mentioned above or the isocyanate may be blocked partially and make it react with the resin skeleton such as described in U.S. Patent No. 3,947.38. Too They can be used as a film-forming resin one component compositions described in U.S. Pat. 4,134,866 and DE-OS No. 2,707,405. Together to the epoxy-amine reaction products, resins film forming can also be selected from resins cationic acrylics such as those described in the Patents US Nos. 3,455 and 3,928,157.

In addition to resins containing salt group of amine, resins containing salt group of quaternary ammonium Among the examples of these resins are the formed by reacting an organic polyepoxide with a salt of tertiary amine These resins are described in the Patents Americans Nos. 3,962,165; 3,975,346; and 4,001,101. Between the Examples of other cationic resins are resins that contain ternary sulfonium salt group and resins containing salt group of quaternary phosphonium such as those described in the Patents US Nos. 3,793,278 and 3,984,922, respectively. Be they can also use film-forming resins that cure through transesterification such as those described in the European Patent Application No. 12463. In addition, the cationic compositions prepared from Mannich bases such as those described in US Patent No. 4,134,932.

The resins with which the present invention is particularly effective are positively charged resins that They contain primary and / or secondary amine groups. These resins are described in US Patent Nos. 3,663,389; 3,947,339; and 4,116,900. In U.S. Patent No. 3,947,339, it is made reacting a polythimine derivative of a polyamine such as diethylenetriamine or triethylenetetraamine with a polyepoxide. When he reaction product is neutralized with acid and dispersed in water, Free primary amine groups are generated. Products are also formed equivalents when the polyepoxide is reacted with excess of polyamines such as diethylenetriamine and triethylenetetraamine and the excess amine is drawn in vacuo from the reaction mixture. These products are described in US Pat. Nos. 3,663,389 and 4,116,900.

The electrodepositable ionic resin it contains active hydrogen described above is present in the bath of electrodeposit of the invention in amounts of about 1 to about 60 percent by weight, preferably of about 5 to about 25 based on the total weight of the electrodeposit bath.

The resinous phase of the electrodeposition bath of The present invention further comprises (b) a curing agent adapted to react with the active hydrogen groups of the electrodepositable resin (a) just described. Both of them Aminoplastic and blocked organic polyisocyanate curing agents they are suitable for use in the present invention, although here prefer locked isocyanates for electrodeposition cationic

Aminoplast resins, which are the agents of preferred curing for anionic electrodeposition, are products of condensation of amines or amides with aldehydes. Among the examples of Suitable amine or amide are melamine, benzoguanamine, urea and similar compounds. Generally, the aldehyde used is formaldehyde, although products from other aldehydes can be obtained such as acetaldehyde and furfural. Condensation products they contain methylol groups or similar alkylol groups depending on the particular aldehyde employed. Preferably, these methylol groups they are etherified by reaction with an alcohol. Among the various alcohols used include monohydric alcohols that they contain 1 to 4 carbon atoms such as methanol, ethanol, isopropanol and n-butanol, the preferred being methanol Aminoplast resins are available commercially from American Cyanamid Co. under the trademark CYMEL and Monsanto Chemical Co. under the trademark RESIMENE

Aminoplast curing agents are typically used in conjunction with anionic electrodepositable resin which contains active hydrogen in amounts that vary from about 5 percent to about 60 percent in weight, preferably about 20 percent to approximately 40 percent by weight, the percentages being based on the total weight of resin solids in the bath of electodeposit.

Preferred curing agents for use in cathodic electrodeposition are blocked organic polyisocyanates. The polyisocyanates can be completely blocked as described in US Patent No. 3,984,299 column 1, lines 1 to 68, column 2 and column 3 lines 1 to 15, or partially blocked and make them react with the polymer skeleton as is described in U.S. Patent No. 3,947,338 column 2, lines 65 to 68, column 3 and column 4, lines 1 to 30, which incorporate here as a reference. "Blocked" means that isocyanate groups have been reacted with a compound of so that the resulting blocked isocyanate group is stable at hydrogens active at room temperature but reactive with active hydrogens of the film forming polymer at temperatures high, usually between 90ºC and 200ºC.

Suitable polyisocyanates include aromatic and aliphatic polyisocyanates, among which are cycloaliphatic polyisocyanates and are representative examples diphenylmethane-4,4'-diisocyanate (MDI), 2,4- or 2,6-toluene diisocyanate (TDI), including mixtures thereof, diisocyanate p-phenylene, tetramethylene diisocyanates and hexamethylene, dicyclohexylmethane-4,4'-diisocyanate, Isophorone diisocyanate, mixtures of phenylmethane-4,4'-diisocyanate and polymethylene polyphenyl isocyanate. Can be used higher polyisocyanates such as triisocyanate. An example will include triphenylmethane-4,4 ', 4' '- triisocyanate. You can also use () -prepolymers of isocyanate with polyols such as neopentyl glycol and trimethylolpropane and with polymeric polyols such as polycaprolactone diols and triols (ratio of NCO / OH equivalents greater than 1).

Polyisocyanate curing agents are used. typically in conjunction with electrodepositable cationic resin that contains active hydrogen in amounts that vary from about 5 percent to about 60 percent in weight, preferably about 20 percent by weight to approximately 50 percent by weight, based on the percentages in The total weight of resin solids in the bath of electrodeposit.

The aqueous compositions of the present invention are in the form of an aqueous dispersion. The term "dispersion" is used to indicate a resinous system transparent, translucent or opaque in two phases in which the resin is in the dispersed phase and the water is in the continuous phase. The size Particle medium of the resinous phase is usually less than 1.0 and normally less than 0.5 microns, preferably less than 0.15 microns

The concentration of the resinous phase in the aqueous medium is at least 1 and usually from about 2 to about 60 percent by weight based on the total weight of the aqueous dispersion. When the compositions of the present invention are in the form of resin concentrates, they generally have a resin solids content of about 20 to about 60 percent by weight based on the weight of the dispersion
watery

The electrodeposition baths of the invention are They typically supply as two components: (1) a feed of transparent resin, which usually includes the resin electrodepositable ionic containing active hydrogen, that is, the main film forming polymer, the curing agent, and any additional non-pigmented water dispersible component; Y (2) a pigment paste that generally includes one or more pigments, a water dispersible crushing resin that can be the same or different from the main polymer that forms a film and, optionally, additives such as wetting agents and dispersants The components of the electrodeposition bath (1) and (2) they are dispersed in an aqueous medium comprising water and, normally coalescing solvents.

It should be noted that there are several methods whereby the yttrium compound can be incorporated into the bath of electrodeposit. A soluble yttrium compound can be added "net" that is, add it directly to the bathroom without prior mixed or reaction with other components. Alternatively, it you can add a soluble yttrium compound to the feed of pre-dispersed transparent resin that may include ionic resin, curing agent and / or any other component non-pigmented Preferably, the soluble compound of yttrium is added "net" to the electrodeposit tank. The insoluble yttrium compounds and / or yttrium pigments, on the other part, they are preferably pre-mixed with the component of pigment paste before incorporating the paste into the bath of electrodeposit.

The electrodeposition bath of the present invention may contain yttrium as the only inorganic component that inhibits corrosion or may be supplemented with other components organic or inorganic corrosion inhibition such as calcium, bismuth or polyphenols, such as functional polymers phenol. Preferably the electrodeposition bath is free of lead.

The electrodeposition bath of the present invention has a resin solids content that is normally within the range of about 5 to 25 per weight percent based on total bath weight of electrodeposit.

As mentioned before, in addition to water, the Aqueous medium may contain a coalescing solvent. Between the useful coalescing solvents include hydrocarbons, alcohols, esters, ethers and ketones. Coalescing solvents Preferred include alcohols, polyols and ketones. Solvents Specific coalescers are isopropanol, butanol, 2-ethylhexanol, isophorone, 2-methoxypentanone, ethylene and propylene glycol and monoethyl, monobutyl and monohexyl ethers of ethylene glycol. The amount of coalescing solvent is usually of approximately 0.01 to 25 percent and, in practice, is preferably from about 0.05 to about 5 per weight percent based on the total weight of the aqueous medium.

As discussed before, it can be included in the dispersion a pigment composition and, if desired, several additives such as surfactants, wetting agents or catalyst. The pigment composition can be of the type conventional comprising pigments, for example, iron oxides, strontium chromate, carbon black, carbon powder, dioxide titanium, talc, barium sulfate, as well as color pigments such like cadmium yellow, cadmium red, chrome yellow and Similar. The pigment content of the dispersion is expressed normally as the ratio of pigment to resin. In the practice of the invention, when pigment is used, the pigment ratio to resin is normally within the range of about 0.02 to 1.1. The other additives mentioned above are normally in the dispersion in amounts of about 0.01 to 3 percent in weight based on the weight of resin solids.

Coating compositions electrodepositable of the present invention can be applied by electrodeposition to a variety of electroconductive substrates, especially metals such as untreated steel, steel galvanized, aluminum, copper, magnesium and coated materials conductive carbon The applied electrical voltage for electrodeposit can vary and can be, for example, as low as 1 volt to as high as several thousand volts, but It is typically between 50 and 500 volts. Current density is normally between 0.5 amps and 5 amps per square foot (per 0.09 m 2) and tends to decrease during electrodeposition which indicates the formation of an insulating film.

Once applied the coating by electrodeposition, it is normally cured by baking at temperatures elevated such as about 90 ° C to about 260 ° C for about 1 to 40 minutes.

The following examples are illustrative of the invention, which is not to be considered however limited to details of them. All parts and percentages in following examples as well as throughout the specification They are by weight unless otherwise indicated.

Examples

Examples A and B describe the preparation of cationic electodepositable resins, Example A also contains a polyurethane crosslinker. Examples C and D describe, each of them, the preparation of crushing resins with pigment that they contain quaternary ammonium salt.

Examples AA and BB describe the preparation of a pigment paste for use in bath compositions of electrodeposit of the invention. Examples CC and DD describe the preparation of bath pre-mixtures of electrodeposit for use in the compositions of electrodeposition baths of Examples 1 and 2, and Examples 3 and 4, respectively. Example EE describes the preparation of the soluble yttrium solution for use in the compositions of Example 2 and 4. Table 1 illustrates the improvement in corrosion resistance of punch drag observed with the inclusion of soluble yttrium solution in compositions free of lead of the electrodeposition bath of the invention.

Example A

A polyurethane crosslinker was prepared from a mixture of the following ingredients

one

 \ begin {minipage} [t] {153mm} ^ {1} Bisphenol A adduct and a dialcohol containing 6 ethylene oxide, available commercially as MACOL 98 A MOD1 of BASF Corp. \ end {minipage}  \ begin {minipage} [t] {153mm} ^ {2}    polymeric methylene diphenyl diisocyanate from Dow Chemical Co. \ end {minipage}

They were added to a round bottom flask of 12 liters, properly equipped, the ingredients of Load I. It heated these ingredients with gentle stirring under the atmosphere of nitrogen at a temperature of 50 ° C. PAPI 2940 was added gradually over a period of approximately 2 hours raising the temperature to 110 ° C, followed by a rinse of approximately 176.6 grams of methyl isobutyl ketone. The reaction mixture at 110 ° C to 110 ° C until it was not detected Isocyanate by infrared spectroscopy. The remaining 1072.7 grams of methyl isobutyl ketone were then added to the mixture of reaction, which had a final solids content of approximately 83% (1 hour at 110 ° C).

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A cationic resin was prepared from a mixture of the following ingredients:

2

       \ dotable {\ tabskip \ tabcolsep # \ hfil \ tabskip0ptplus1fil \ dddarstrut \ cr} {
  1 Bisphenol A glycidyl ether marketed by Shell
Oil and Chemical Co. \ cr \ begin {minipage} [t] {153mm} 2
Adduct prepared from a 1: 2 molar ratio of Bisphenol A
      ethoxylated (9 moles of ethylene oxide per mole of bisphenol A)
and hexahydrophthalic anhydride mixed in the presence of
0.05% triethylamine catalyst and maintained at 100 ° C
for 3.5 hours. \ end {minipage} \ cr3 Agent
commercial surfactant from BASF Corp. \ cr
 \ begin {minipage} [t] {153mm} ^ {4} Reaction product of 2
moles of diethylene glycol monobutyl ether and 1 mole of
formaldehyde, 98% active, prepared as described in the Patent
U.S. No. 4,891,111 to McCollum and
col. \ end {minipage} \ cr5 {Marketed by Huntsman
Corporation. \ Cr}
    

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To a 12-liter round bottom flask, properly equipped, the ingredients of Charge 1 were added. The reaction mixture was stirred with gentle stirring and heated under a nitrogen layer at a temperature of approximately 75 ° C, followed by the addition of Load II The reaction mixture was allowed to develop an exotherm and once the exotherm was finished, the reaction temperature was adjusted to approximately 120 ° C to 123 ° C and maintained at that temperature for approximately 2 hours. The reaction mixture had an epoxide equivalent weight greater than 20,000 based on solids, an amine content of 0.77 milliequivalents per gram based on solids, and a Gardner-Holdt bubble viscosity of S / T (when reduced to 50 % solids with 1-methoxy-2-
propanol).

An aqueous dispersion of the resin was prepared cationic prepared before from a mixture of the following ingredients:

3

 \ begin {minipage} [t] {153mm} ^ 1 solution at 30% of turpentine turpentine (marketed by Aldrich Chemical Company. Inc.) in methyl isobutyl ketone. \ end {minipage}

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Charge 1 was added to a bath equipped with a stirrer and heated to a temperature of 50 ° C. The cationic resin was added at this temperature and mixed for approximately 30 minutes until thoroughly dispersed while turpentine turpentine was gradually added (Charge III). The cationic resin and turpentine turpentine were mixed for 15 minutes, then adding the deionized water of Charge IV. The dispersion was heated to a temperature of approximately 60 ° to 65 ° C and subjected to reduced pressure of approximately 20 inches of mercury (500 mm of mercury) over a period of approximately 2 hours during which the methyl isobutyl ketone was removed by vacuum distillation. The resulting dispersion had 41.9% solids (1 hour at
110 ° C).

Example B

A cationic resin was prepared from a mixture of the following ingredients

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(Table goes to page next)

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 \ begin {minipage} [t] {153mm} ^ {1} Bisphenol A adduct and a dialcohol containing 6 ethylene oxide marketed as MACOL 98 A MOD1 by BASF Corp. \ end {minipage}  \ begin {minipage} [t] {153mm} ^ {2}   Reaction product of 2 moles of diethylene monobutyl ether glycol and 1 mol of formaldehyde, 98% active, prepared as is described in U.S. Patent No. 4,891,111 to McCollum and others. \ end {minipage}  \ begin {minipage} [t] {153mm} ^ {3}   Dicetimin derived from diethylenetriamine and methyl isobutyl ketone (73% of solids in methyl isobutyl ketone) prepared as described in U.S. Patent No. 3,947,339 to Jerabel and others. \ end {minipage}

To a 6-liter flask, properly equipped, the ingredients of Charge I were added under gentle agitation and in the order shown above. The reaction mixture was heated to a temperature of 125 ° C under nitrogen atmosphere, it was left after the exotherm will develop at a temperature of approximately 145 ° C to 160 ° C and then held for one hour at a temperature of approximately 145 ° C. The reaction mixture is then cooled to a temperature of about 125 ° C adding then the ingredients of Charge II and the reaction mixture for an additional two hours at that temperature. After the maintenance period, it was slowly poured approximately 85% of the reaction product in a solution of acetic acid (28.9 g (0.481 equivalents) and 190.0 grams of water deionized and allowed to mix for 30 minutes. Water was added additional deionized to reduce dispersed solids to 36% (1 hour @ 110ºC). The vacuum dragging of the cationic dispersion to separate methyl isobutyl ketone.

Example C

This example describes the preparation of a crushing resin with pigment containing ammonium salt quaternary. Example C-1 describes the preparation of an amino acid salt quaternizing agent and Example C-2 describes the preparation of a polymer that contains epoxy group that subsequently quaternizes with salt amino acid of Example C-1.

Example C-1

The quaternizing agent amino acid salt is Prepared using the following procedure.

To a suitably equipped 5 liter flask, 445 parts by weight of N, N-dimethylethanolamine were added. 660 parts by weight of PAPI 2940 (polymeric diisocyanate marketed by Dow Chemical Co.) were added slowly with a gentle stirring over a period of 1.5 hours, followed by rinsing with 22.1 parts by weight of the solvent mentioned above for Examples A and B. During this addition, the exotherm of the reaction mixture was allowed to develop at a temperature of approximately 89 ° C and maintained at that temperature approximately 1 hour until the reaction of the isocyanate determined by infrared spectroscopy was completed. 512 parts by weight of an 88% aqueous solution of lactic acid were then added over a period of 25 minutes, followed by the addition of approximately 2136.11 parts by weight of deionized water. The reaction temperature was maintained at about 80 ° C for about 6 hours until a stable value of
acid.

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Example C-2

A polymer containing salt group of quaternary ammonium using the following procedure.

A properly equipped 5-liter flask is added, under gentle agitation, 528.8 parts by weight of EPON 828 (Bisphenol A polyglycidyl ether marketed by Shell Oil and Chemical Co); 224.9 parts by weight of Bisphenol A; 83.7 parts in weight of the solvent mentioned above in Examples A and B; and 0.5 parts by weight of ethyltriphenylphosphonium iodide. It warmed up reaction mixture at about 140 ° C, the exotherm to about 180 ° C and then cooled to approximately 160 ° C and was maintained at that temperature for about 1 hour. At that time the polymer product had an epoxide equivalent weight of 982.9. The reaction mixture is then cooled to a temperature of about 130 ° C then approximately164.9 parts by weight of the solvent of Examples A and B and the temperature was lowered to approximately 95 ° C-100 ° C, followed by the addition of approximately 418.4 parts by weight of the quaternization agent amino acid of Example C-1 over a period 15 minutes, and then followed by the addition of approximately 1428.1 parts by weight of deionized water. The reaction temperature was maintained at about 80 ° C for approximately 6 hours until the acid index of the product of reaction was below 1.0. Crushing resin with pigment containing resulting quaternary ammonium salt group it was further diluted with approximately 334.7 parts by weight of the solvent of Examples A and B.

Example D

This example describes the preparation of a second crushing resin with pigment containing salt group of quaternary ammonium. Example D-1 describes the preparation of a quaternizing agent amino acid salt and the Example D-2 describes the preparation of a polymer containing epoxy group that subsequently quaternizes with the acid-amine salt of the Example D-1

Example D-1

The quaternizing salt agent of acid-amine using the following process.

To a 5-liter flask, properly equipped, 267.4 parts by weight of were added while stirring N, N-dimethylethanolamine. At a temperature of at approximately 23 ° C, 396 parts by weight of PAPI 2940 for 1.0 hour, followed by rinsing with approximately 13.9 parts by weight of the aforementioned solvent in Examples A and B. The temperature of the exotherm at about 90 ° C during the addition and held subsequently at that temperature for about 45 minutes until the isocyanate disappeared which was determined by infrared spectroscopy. 112.8 parts were then added in dimethylcocoamine weight followed by the addition of approximately 361.3 parts by weight of 88% aqueous lactic acid solution at over a period of 15 minutes. Were added then approximately 695.0 parts by weight of deionized water and the reaction temperature was maintained at about 85 ° C for approximately 3 hours until the acid index obtained was stable.

Example D-2

A polymer containing ammonium salt was prepared Quaternary using the following procedure.

A properly equipped 5-liter flask is added 631.7 parts by weight of EPON; 828; 268.7 parts by weight of Bisphenol A; 10.0 parts by weight of the solvent of Examples A and B; and 0.6 parts of ethyltriphenylphosphonium iodide. The mixture of reaction was heated to about 140 ° C and allowed to develop the exotherm to a temperature of approximately 180 ° C. then the reaction was cooled to 160 ° C and staying for approximately 1 hour at an equivalent weight of 991.0 epoxide. The reaction was cooled further to approximately 130 ° C and 421.2 parts by weight of ethoxylated Bisphenol A (6 moles of ethylene oxide per mole of Bisphenol A). Continued cooling to a temperature of approximately 80 ° C, at which time 346.4 parts by weight of agent were added quaternizing amino acid salt of Example D-1 a over a period of approximately 30 to 35 minutes followed by the addition of 404.8 parts by weight of deionized water. The mixture of reaction was maintained at a temperature of about 80 ° C for about 6 hours until the acid index dropped below 1.0. The crushing resin with pigment that contained resulting quaternary ammonium salt group was diluted also with 2232.2 parts of deionized water.

Example AA

This Example describes the preparation of a paste of pigment suitable for use in bath compositions of electrodeposit of the present invention. The pigment paste is Prepared from a mixture of the following ingredients:

5

1 Agent non-ionic surfactant marketed by Air Products and Chemicals, Inc. 2 E.I. Titanium Dioxide Pigment Dupont de Nemours  \ textamp Co (Inc.) 3 Cabot carbon black pearls Corp. 4 Catalyst Paste prepared from a mixture of the following ingredients:

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6

1 Oxide catalyst di-n-butyltin from Sankyo Organic Chemicals Co, Ltd.

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The above ingredients were added, in the order shown and under high shear effect agitation. One time thoroughly mixed the ingredients, the pigment paste was passed to a vertical sand mill and was ground to a Hegman value of approximately 7.25.

BB example

This example describes the preparation of a paste of pigment suitable for use in bath compositions of electrodeposit of the present invention. The pigment paste is Prepared from a mixture of the following ingredients:

7

1 Agent Air Products and Chemicals surfactant, Inc. 2 Pigment Dioxide E.I. titanium Dupont de Nemours \ textamp Co. (Inc.) 3 carbon black pearls of Cabot corp. 4 Oxalate Hydrate of calcium marketed by Aldrich Chemical Company, Inc. 5 Catalyst Paste prepared from a mixture of the following ingredients:

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The previous ones were added sequentially ingredients using high shear agitation. One time thoroughly mixed the ingredients, the pigment paste was passed to a vertical sand mill and was ground to a Hegman value of approximately 7.25.

CC example

This example describes the preparation of a Pre-mix electrodeposit bath for your use in electrodeposition bath compositions of Examples 1 and 2 given below. The pre-mix of the bathroom of electrodeposit was prepared from a mixture of following ingredients:

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 \ begin {minipage} [t] {153mm} ^ {1} Reaction product of JEFFAMINA D400 (polyoxypropylene diamine from Huntsman Corporation) and DER-732 (commercially aliphatic epoxide available from Dow Chemical Co.), prepared as described in the U.S. Patent No. 4,423,166 to Moriarity and others. \ end {minipage}  \ begin {minipage} [t] {153mm} ^ {2}  Methylamine reaction product; propylene's OXID; and toluen diisocyanate as described in US Patent No. 5,348,578. \ End {minipage} 3 Acid phenylphosphonic marketed by Aldrich Chemical Company, Inc.).

DD example

This example describes the preparation of a Pre-mix electrodeposit bath for your use in electrodeposition bath compositions of Examples 3 and 4 below. The pre-mix of electrodeposition bath was prepared from a mixture of the following ingredients:

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1 Acid phenylphosphonic marketed by Aldrich Chemical Company, Inc.

EE example

This example describes the preparation of a soluble yttrium solution for use in the compositions electrodeposition bath of Example 2 and 4 below. The solution soluble yttrium was prepared from the mixture of the following ingredients:

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1 Available commercially from Aldrich Chemical Company, Inc.

Examples 1 to 4

Examples 2 and 4 describe the preparation of electrodeposit bath compositions of the invention which contain 500 ppm of the soluble yttrium solution of Example EE. Comparative Examples 1 and 3 do not contain yttrium solution soluble. The electrodeposition bath compositions were prepared from a mixture of the following ingredients:

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Preparation of the electrodeposition bath

The resin was diluted while stirring cationic of Example B with approximately 15% of the total water deionized The resin diluted in the resin was then stirred cationic of Example A. The flexibilizing resin was diluted separately while stirring the solvent, it was further diluted with approximately 30% total deionized water before add it to the cationic resin mixture. The flow control additive. The phenylphosphonic acid was diluted with approximately 5% of the total deionized water before adding to the cationic resin mixture. The pigment paste was diluted separately with the rest of deionized water and added to the previous resin mixture. The final bath solids were of approximately 22.5% with a pigment to resin ratio of 0.12: 1.0. The test baths were 20% ultrafiltered and were filled only with fresh deionized water for the Examples Comparatives 1 and 3, and with fresh deionized water and the amount of soluble yttrium solution prescribed in Examples 2 and 4 before electrolytic coating

Electrolytic coating procedure

Each electrodeposition bath composition of Examples 1 to 4 above were electrodeposited on panels of non-phosphated cold rolled steel, marketed by ACT Laboratories The conditions for each electrodeposition were the following: 2 minutes at 90ºF (36.6ºC) at 160-180 volts to give a film thickness cured from 0.6 to 0.8 mils (1.5 to 2 mm). The coated substrate is cured in an electric stove at 340ºF (171ºC) for 20 minutes

Test procedure

The punch was applied to each of the panels of untreated steel test, making a cut through the coating to the metal substrate in an "X" drawing. The test panels were then subjected to a test of salt spray according to ASTM B117. Test panels were evaluated for corrosion of "punch drag" and visual aspect. The dragging of the punch is expressed as distance average (in millimeters) of corrosion from the punch mark The Test results are given in the following Table 1

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The data given in the table above illustrates the Improved corrosion resistance of punch drag observed with the inclusion of soluble yttrium solutions in the bathroom of electrodeposit of the invention.

Claims (16)

1. A coating composition electrodepositable comprising a resinous phase dispersed in a aqueous medium, said resinous phase comprising:

(to)

  an electrodepositable ionic resin containing hydrogen group active, and

(b)

  a curing agent that has reactive functional groups with the active hydrogen groups of (a)

where the composition comprises less a yttrium compound that is soluble in aqueous medium and is present in an amount of about 0.005 percent by weight at about 5 weight percent yttrium based on weight of the total resin solids of the coating composition electrodepositable 2. The coating composition electrodepositable according to claim 1 wherein the amount of Yttrium present is not more than approximately 1.0 percent in weight based on the weight of the total resin solids in the electrodepositable coating composition. 3. The coating composition electrodepositable according to claim 1 wherein said Composition is substantially lead free. 4. The coating composition electrodepositable according to claim 1 wherein said phase Resinosa also comprises at least one lead-free pigment. 5. The coating composition electrodepositable according to claim 1 wherein said Yttrium compound is selected from the group consisting of nitrate of yttrium, yttrium acetate, yttrium chloride, yttrium sulfamate, Yttrium lactate, yttrium formate and mixtures thereof. 6. The coating composition electrodepositable according to claim 1 wherein said yttrium compound is a soluble salt of yttrium selected from group consisting of yttrium sulfamate, yttrium acetate, lactate of yttrium, yttrium formate and yttrium nitrate. 7. The coating composition of the claim 1 wherein the ionic resin containing hydrogen Active is cationic. 8. A coating composition electrodepositable comprising a resinous phase dispersed in a aqueous medium, said resinous phase comprising:

(to)

  a active hydrogen group containing ionic resin electrodepositable, and

(b)

  a curing agent that has reactive functional groups with the active hydrogen groups of (a)

where the composition comprises less a yttrium compound that is soluble in aqueous medium and is present in an amount of approximately 10 parts per million to approximately 10,000 parts per million yttrium, based on weight from the bathroom of electrodeposit. 9. The electrodeposition bath according to the claim 8 wherein the amount of total yttrium is not greater than approximately 1,000 parts per million based on bathroom weight of electrodeposit. 10. The electrodeposition bath according to the claim 8 wherein the amount of total yttrium is not greater than approximately 500 parts per million based on the weight of the bathroom electrodeposit. 11. The electrodeposition bath according to the claim 8 wherein said bath is substantially free of lead. 12. A coating composition that It contains the following components:

(to)

  a resin containing active hydrogen group; Y

(b)

  a curing agent that has reactive functional groups with the         active hydrogen groups of (a)

where the composition of coating comprises approximately 0.005 percent by weight at approximately 5.0 percent by weight of yttrium based on the weight of total resin solids in the composition of covering. 13. An electrolytic coating method of a conductive substrate that serves as an electrode charged in a electrical circuit comprising said electrode and a counter-electrode charged with opposite charge, being the electrodes submerged in an electrodeposition bath aqueous according to any of the claims 8-11, which includes the flow of current electrical between the aforementioned electrodes to deposit the electrolytic coating composition on the substrate as substantially continuous film. 14. The method according to claim 13 where the substrate is the cathode. 15. The method according to claim 13 where said substrate consists of untreated steel. 16. The method according to claim 13 where said substrate consists of galvanized steel.